SURFACE CLEANING EFFECT ON DIELECTRIC INTEGRITY FOR ULTRATHIN OXYNITRIDES GROWN IN N2O

In this study, we developed a wafer-cleaning procedure for ultrathin d ielectric growth. This involves a modified RCA clean, a dilute-HF dip and a subsequent immersion in methanol/HF solution. Ultrathin (almost- equal-to 42 angstrom) oxynitride films were grown in pure N2O using th is new cleaning procedure and some other schemes to investigate the ef fects of surface preparation on dielectric integrity. Devices fabricat ed by this new cleaning procedure were found to exhibit the lowest lea kage current level and the best breakdown performance among all sample s. The variation in the current-voltage characteristics across a 4-in. wafer was also minimized by this two-step dipping process. The result s suggest that the new cleaning procedure is desirable to yield high-q uality ultrathin dielectrics.